交易撮合系統···實現得比較簡陋

#include <iostream>
#include <queue>
#include <algorithm>
#include <map>
 
using namespace std;
class Exchange {
 
public:
	static int count; //靜態數據變量爲每個委託賦予獨一無二的id
	static bool match(const Exchange &a, const Exchange &b)
	{
		return a.price >= b.price;
	}
	int id;
	int direction;
	int volum;
	int price;
	int num;
	Exchange(int d, int v, int p)
	{
		count++;
		direction = d;
		volum = v;//委託量
		price = p;
		id = count;
		num = 0;  //交易量
	}
	static int chaxun(int id, map<int, int> &unfinished, map<int, int> &finished);
 
};
int Exchange::chaxun(int id, map<int, int> &unfinished, map<int, int> &finished)
			{
	          map<int, int>::iterator i=unfinished.find(id);
			  if (i != unfinished.end())
				  return i->second;
			  else i = finished.find(id);
 
				  if (i != finished.end())
					  return i->second;
				  else return -1;
}
int Exchange::count = 0;
 
struct cmp1 {
	bool operator()(const Exchange &a, const Exchange &b)const
	{
		if (a.price == b.price)
			return a.id < b.id;
		else
			return a.price < b.price;
 
	}
};
struct cmp2 {
	bool operator()(const Exchange &a, const Exchange &b) const
	{
		if (a.price == b.price)
			return a.id > b.id;
		else
			return a.price < b.price;
 
 
	}
};
 
void update(Exchange a, Exchange b, priority_queue<Exchange, vector<Exchange>, cmp1> &input, priority_queue<Exchange, vector<Exchange>, cmp2> &output, map<int, int> &unfinished)
{
	input.pop(); output.pop();  //優先級隊列的TOP元素爲只讀，修改內容需要先彈出，再修改，最後重新壓入
 
	int temp = min(a.volum, b.volum);
	unfinished[a.id] = a.volum -= temp;
	a.num += temp;
	unfinished[b.id] = b.volum -= temp;
	b.num += temp;
	input.push(a); output.push(b);
}
char inputc()
{
	char a;
	cin >> a;
	return a;
}
void exchange(priority_queue<Exchange, vector<Exchange>, cmp1> &input, priority_queue<Exchange, vector<Exchange>, cmp2> &output, map<int, int> &unfinished, map<int, int> &finished)
{
	        int d, v, p;
	
			cin >> d >> v >> p;
 
			if (d != 0 && d != 1)
			{
				cout << "\t您的委託類型輸入有誤，請重新輸入：" << endl;
				cin.clear();
				cin.ignore(numeric_limits<streamsize>::max(), '\n');
			}                                //如果不清除緩存區，就有可能輸出多條錯誤提示
			if (d == 0)
			{
				priority_queue<Exchange, vector<Exchange>, cmp1>::value_type a(d, v, p);
				input.push(a);
				unfinished[a.id] = a.volum;
			}
			if (d == 1)
			{
				priority_queue<Exchange, vector<Exchange>, cmp2>::value_type a(d, v, p);
				output.push(a);
				unfinished[a.id] = a.num;
			}
			if (input.empty() || output.empty())
				return;
 
			while (!input.empty() && !output.empty())
			{
				if (Exchange::match(input.top(), output.top()))
				{
					Exchange p1(input.top());
					Exchange p2(output.top());
					update(p1, p2, input, output, unfinished);
 
					if (input.top().volum == 0)
					{
						unfinished.erase(input.top().id);   //如果委託量爲零，則全部轉入已交易的映射中
						finished[input.top().id] = input.top().num; 
						input.pop();
					}
					if (output.top().volum == 0)
					{
						unfinished.erase(output.top().id);
						finished[output.top().id] = output.top().num;
						output.pop();
					}
 
				}
				else
					{ 
					cout << "\n";
					cout << "\t交易進行完成" << endl;//委託隊列非空但不滿足繼續交易的條件
					cout << "\n";
					return;
					}
 
			}
			cout << "\t交易進行完成" << endl;       //有至少一方的委託隊列爲空，交易完成
			
		
		
 
	
}
int main()
{
	
	priority_queue<Exchange, vector<Exchange>, cmp1>input;
	priority_queue<Exchange, vector<Exchange>, cmp2>output;
	map<int, int> finished;   //用map存放已完成的交易信息，檢索速度很快
	map<int, int> unfinished; //用map存放未完成的交易信息
	
	cout << "\t歡迎使用本交易系統"<<endl;
	
	while (1)
	{   cout << "\t  查詢請按q\n\t  發出委託請按w\n\t  退出請按z"<<endl;
		char temp = inputc();
		if (temp == 'w')
		{
			cout << "\t確認發出委託請按y,返回上層請按n："<<endl;
			char t;
			cin >> t;
			if (t == 'y')
			{
				cout << "\t請輸入委託類型，委託量，委託價格："<<endl;
				exchange(input, output, unfinished, finished);
			}
			else if (t == 'n')
				continue;
			else
			{
				cout << "\t您的輸入有誤，請重新輸入：" << endl;
				cin.clear();
				cin.ignore(numeric_limits<streamsize>::max(), '\n');//如果不清除緩存區，就有可能輸出多條錯誤提示
				continue;
			}
		}
		else if (temp == 'q')
		{
			int id;
			cout << "\t請輸入委託單號：" << endl;
			cin >> id;
			if (Exchange::chaxun(id, unfinished, finished) != -1)
			{
				cout << "\n";
				cout << "\t第" << id << "單委託的交易量爲" << Exchange::chaxun(id, unfinished, finished) << endl;
				cout << "\n";
			}
			else
				cout << "\t並無此單，請重新輸入" << endl;
		}
		else if (temp == 'z')
		{
			cout << "\t謝謝使用，再見！"<<endl;
			break;
		}
		else
		{
			cout << "\t您的輸入有誤，請重新輸入：" << endl;
			cin.clear();
			cin.ignore(numeric_limits<streamsize>::max(), '\n');
			continue;
		}
	}
	
	
	return 0;
}